Wednesday, October 22, 2014 [Tweets] [Favorites]

Lebeaupin on Swift

Pierre Lebeaupin:

Nested block comments do not work. They cannot be made to work (for those who care, I filed this as rdar://problem/18138958/, visible on Open Radar; it was closed with status “Behaves correctly”). That is why the inside of an #if 0 / #endif pair in C must still be composed of valid preprocessing tokens.

[…]

Little did I know that not only Swift method calls are not more dynamic than Objective-C method calls, but in fact don’t use objc_msgSend() at all by default! Look, objc_msgSend() (and friends) is the whole point of the Objective-C runtime. Period. Everything else is bookkeeping in support of objc_msgSend(). […] Apple is trying to convince us of the Objective-C-minus-the-C-part lineage of Swift, but the truth is that Swift has very little to do with that, and much more to do, semantically, with C++. This would never have happened had Avie Tevanian still been alive working at Apple.

[…]

I find it very odd that there is no description or documentation of threading in Swift. And yes, I know you can spawn threads using the Objective-C APIs and then try and run Swift code inside that thread; that’s not the point. The point is: as soon as I share any object between two threads running Swift code, what happens?

[…]

I don’t like: the lacks of a narrative, or at least of a progression, in the book. Where is the rationale for some of the less obvious features? Where is the equivalent of Object-Oriented Programming with Objective-C (formerly the first half of “Object-Oriented Programming and the Objective-C Programming Language”)? This matters, we can’t just expect to give developers a bunch of tools and expect them to figure out which tool is for which purpose, or at least not in a consistent way. Providing a rationale for the features is part of a programming language as well.

[…]

Swift seems to go counter to all historical programming language trends: it is statically typed when most of the language work seems to trend towards more loosely typed semantics and even duck typing, it compiles down to machine code and has a design optimized for that purpose when most new languages these days run in virtual machines, it goes for total safety when most new languages have abandoned it. I wonder if Swift won’t end up in the wrong side of history eventually.

[…]

Swift, with its type safety, safe semantics and the possibility to tie variables as part of control flow constructs (if let, etc.), promises to capture programmer intent better than any language that I know of, which ought to ease maintenance and merge operations; this should also help observability, at least in principle (I haven’t investigated Swift’s support for DTrace), and might eventually lead to an old dream of mine: formally defined semantics for the language, which would allow writing proofs (that the compiler could verify) that for instance the code I just wrote could not possibly crash.

1 Comment

For me I find Swift confusing. It has some interesting things but I find it a constant knee jerk. Very much like working in somebody else's C++ code base.

I really don't get the hate out there for Objective-C which I find comfortable and clear. Easy to read. It also makes working with C libraries a breeze. I also like C even though it can be hard looking at old C libraries. Fitting those to Swift seems like a lot of work. In fact, since Cocoa is C and Objective-C based everything feels forced in Swift, like objects in JavaScript or PHP.

I am still giving Swift a chance to wow me but for real stuff I continuall find Objective-C to be whether it's at.

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